Fault-indicating means for signal systems



y 1943- J. H. WHEELOCK' FAULT INDICATING MEANS FOR SIGNAL SYSTEMS Original Filed June 22, 1936 SUPERVISOR) CURRENT OPERATED FULL (l/KPPfNT OPE PA TED ,15/02 Mia 22661004 Patented July 6, 1 943 FAULT-INDICATING MEANS FOR SIGNAL SYSTEMS John H. Wheelock, Fitzwilliam, N. H., assignor to Signal Engineering & Manufacturing Company, New York, N. Y., a corporation of Massachusctts Original application June 22, 1936, Serial No. 86,512, now Patent No. 2,238,144, dated April 15, 1941. Divided and this application February 28, 1940, Serial No. 321,323

1 Glaim.

The present application is a division of my original application, Serial No. 86,512, filed June 22, 1936, for an Alarm signal system, since issued as Patent No. 2,238,144, dated April 15, 1941, and relates particularly to improved means for indicating the occurrence of a fault, power failure, or any abnormal circuit condition, which might occur in a system of the character contemplated by the aforesaid original application, or in any other supervised electrical system.

In Wheelock Patent No. 2,170,104, issued August 22, 1939, there is shown and described an arrangement whereby fault-indicating means for supervising an electrical circuit is also supervised, with provision being made for concurrent supervision of the additional fault-indicating means. As a result, any fault occurring in either the supervised circuit, or in the inter-connected circuits of the dual fault-indicating means, is immediate- 13 called to attention.

The invention of the present application relates to an improved arrangement of the fault-indicating means and interconnected circuits disclosed in my aforesaid Patent No. 2,170,104,

whereby there is obtained additional supervision of certain essential parts of the electrical signal system with which the trouble indicating means is associated. The above and other advantageous features of the invention will hereinafter more fully appear, with reference to the accompanying drawing, in which:

Fig. 1 is a Wiring diagram, illustrating a signal system to which there has been applied crosssupervision of the inter-connected trouble indicating means.

Fig. 2 is a schematic diagram based on Fig. 1, illustrating functioning of the trouble indicating means, upon the occurrence of a fault.

Fig. 3 is a view in side elevation of a circuit controller employed in the signal. system under supervision.

Like reference characters refer to like parts in the different figures.

The invention is shown in Fig. 1, for purposes of illustration, as being embodied in an alarm signal system, in which signals 1 are adapted to be sounded, or otherwise electrically operated, for giving an alarm. The signals l are shown as being of the single-stroke solenoid type with each providing an operating Winding 2 within which moves a magnetic striker 2a; The windings 2 of the signals I are adapted to be connected insections across the supply mains 3 and 6, with balancing resistors 5 between the sections, by means of a number of pairs of relatively movable contacts 6 and 'l forming part of a master controller, generally designated by the reference character A.

Referring to Fig. 3, the master controller A comprises a magnetic core 8, one leg of which is surrounded by an energizing winding 9, while the lower end of the other core leg supports a main armature l0 and an auxiliary armature H, movable independently of the main armature. The main armature it] carries a bar [2 on which are mounted a number of contacts 6 corresponding to the movable'contact-s of the several sets shown in Fig. 1 for controlling energization of the signal windings 2'. These contacts 6 are in the form of arms insulated from the bar l2 at l3 and cooperate with stationary contacts I mounted on an insulating base I4 of the master controller A. Therefore, attraction of the main armature IO, in response to energization of the winding 9, is adapted to simultaneously energize the signal windings 2, in sections, according to the connection of the several pairs of contacts 6 and 'l to the signal windings 2 and to the supply mains 3 and 4.

Referring again to Fig. 1, the winding 9 of the master controller A is shown as having one terminal thereof connected to the supply main 3, While the other terminal thereof is connected in series with a number of alarm sending stations i5, disposed in various locations throughout the system. Each sending station provides a suitable contacting mechanism, here shown as comprising independent pairs of spaced stationary contacts 16, IT and I8, I9, and in the normal, non-operating condition of the station, a circuit is maintained between contacts I6 and I1 by a bridging member 2G, while a second bridging member 2| maintains a circuit between contacts l8 and IS. The bridging members 20 and 2| are insulated from each other and in the operation of a station [5, are turnable in unison by a code wheel 22, and gearing G, so as to establish a circuit between the station contacts I6 and Hi. all as fully described in my aforesaid Patent No. 2,238,144.

In the normal non-operating condition'of the system shown in Fig. 1, all'of the contacts 13 and ll of the several stations 15 are connected in series with the controller winding 3 through the bridging members 23, and the contact ll of the station farthest removed from the winding 9 in the circuit, is connected by a station conductor 23 to a controlling resistor 24. The resistor 24 is in turn connected in series with the signal windings 2 and balancing resistors 5, and the last signal winding 2 is connected to the farthest station contact I8 through a station conductor 25. The circuit extends through the bridged contacts I8 and I9 of the several stations, and a conductor 26 connects the nearest station contact I9 to the main 4 through a current-limiting resistor 21. Normally, a small supervisory current traverses the parts of the system described thus far, as follows:

Beginning at the supply main 4, the supervisory current flows through the resistor 21, bridged station contacts I9 and I8, and through the station conductor 25 to the windings 2 and resistors of the several sections of signals I. The current then passes through the controlling resistor 24 and station conductor 23 to the other series of bridged Station contacts I! and I3, and from thence through the winding 9 of the master controller A to the grounded supply main 3. The value of this supervisory current is such as to energize the winding 9 just enough to attract and hold in the auxiliary armature I I while the main armature I0 remains down; the system remains in supervised condition, in readiness either for the operation of the alarm signals, upon actuation of a sending station, or indication of a fault or any abnormal circuit condition by a troubl signal, without operation of the alarm signals.

One trouble signal 28 provides a solenoid 29 within which operates a magnetic plunger 38 adapted to strike a resonant member 3| in response to full energization of the solenoid 29, one terminal of which is connected to one side of a separate power source, such as battery B, or the supply main 4. The other terminal of solenoid 29 is connected through the normally closed contacts 32 of an interrupter, providing a lever 33 operable when the plunger 39 moves to striking position, and also through a resistor 34 to the other side of source B, or the grounded supply main 3. Resistor 34 limits the current in the solenoid 29 to a small supervisory value, so that the plunger 39 is maintained slightly raised from its lowermost position just out of engagement with normally open contacts 35.

A second or auxiliary trouble signal 28', constructed in the same manner as the trouble signal 28, has one terminal of its solenoid 29 connected to the supply main 4, its other terminal being connected in series with interrupter contacts 32, normally closed pairs of trouble contacts 36 and 31 for the associated alarm system, and a resistor 34 shunted across the open supervisory contacts 35 of the main trouble signal 28. Since resistor 34 is connected to the grounded supply main 3, a small supervisory current flows through the solenoid 29', contacts 35 and 3! and resistor 34'. This supervisory current is sufficient to maintain the plunger 30' above its lowermost position, just out of engagement with normally open contacts 35' connected across the resistor 34 that is in circuit with the solenoid 29.

As best shown in Fig. 3, the trouble contacts 36 are mounted on the base Id of the master controller A, and these contacts 36 are normally bridged by a member 36a mounted on a rod R connected to the free end of the auxiliary armature II. Additional trouble contacts 3'! are held closed by a member 31a, with the armature I9 in its lower position, so that while supervisory current flows through the controller winding 9, the contacts 39 and 31 will be closed to maintain the circuit of the solenoid 29 of the second trouble signal 23.

Upon the occurrence of a break or a ground in the circuit of the signals I and sending stations I5, the auxiliary armature II will fall, thereby opening the trouble contacts 36; or if for any reason armature I9 remains up, opening of contacts 3'! will result.

Referring now to Fig. 2, there is shown a schematic revision of the circuit connections between the various pieces of electrical apparatus illustrated in Fig. 1, the circuit connections being those that exist upon the occurrence of a fault such as a break in the main signal circuit. In this schematic showing, the representations of the controller A, stations I5 and trouble signals 28 and 28' have been greatly simplified so as to give an across-the-line diagram, with the con tacts which are operated by full current and supervisory current indicated by proper legends.

Upon opening of the trouble contacts 36, as indicated in Fig. 2, the flow of supervisory current through the solenoid 29' is interrupted, thereby permitting the plunger 39 to drop, or to pull out as shown schematically. This causes closure of the contacts 35' to short circuit the resistor 34 and thereby fully energize the solenoid 29 of trouble signal 28, whereupon the plunger 30 strikes the resonant member 3I a single stroke. The plunger 30 will give recurring strokes as long as the contacts 35 remain closed, due to the operation of the interrupter contacts 32 by the lever 33. The first trouble signal 29 will therefore continue to operate and indicate the existence of a fault in the system until the cause of the trouble is remedied and the armature II drawn up, upon reestablishment of the main supervisory circuit of the system. Should the main armature I 9 remain up, the signal 28 will be operated, as described above, until the contacts 3'! are again closed, by the bridging member 31a on the armature ID.

If there should occur a break in the circuit of the first trouble signal 28, or a ground, where a grounded source is used, or should the source B fail, the resulting deenergization of the solenoid 29 will cause the plunger 30 to move into the position, indicated in dotted lines in Fig. 2, thereby closing the contacts 35 to short circuit the resistor 34 in circuit with the solenoid 29'. When this occurs, the second trouble signal 28' will operate until the cause of trouble is removed. Furthermore, a break in the circuit of the second trouble signal 28 or failure of mains 3 and 4 will have the same effect as opening the trouble contacts 36 or 31, thereby short circuiting the resistor 34 and causing the first trouble signal 28 to operate. There is thus provided continuous cross supervision of the trouble signal circuits and the alarm system circuit associated therewith, it being noted that the interconnecting conductors between the several circuits, as well as the trouble indicating contacts 36 and 31, are always supervised.

From the foregoing, it is apparent that by the present invention there is provided an improved arrangement of a fault-indicating means for Signal systems, whereby a continuous supervision is obtained for the system, and the fault-indicating signals, as well as the connections therebetween. As a result, any fault occurring in either the supervised system, or in the interconnected circuits of the dual indicating means, is immediately called to attention.

I claim:

In combination with a normally closed electrical circuit, including a controller having a winding traversed by a supervisory current insufiicient to cause operation of the controller, separate fault-indicating signals, means including contacts normally closed in response to the flow of supervisory current through said controller winding for maintaining a flow of supervisory current through one of said signals, insufiicient to cause operation of the same, means for maintaining a flow of supervisory current through the other signal, insuflicient to cause operation of the same, means for operating either signal upon interruption of the flow of supervisory current in the other signal, with said controller-actuated contacts serving to additionally cause operation of the second-named signal, in response to the occurrence of a fault in' said closed circuit and the interruption of supervisory current through said controller winding.

JOHN H. WHEELOCK. 

